Chip duster



2 Sheets-Sheet l 1 y Q? W Oct. 3, 1933.

S. NORMAN CHIP DUSTER Fil'ed Oct. 23 1931 2 Sheets-Sheet 2 it to Patented Oct. 3, 1933 PATENT OFFICE onrr DUSTER Sigurd Norman, Everett, Wash., assignor to Fibre Making Processes, Inc., ChicagoJlL, a corporation of Illinois Application October 23', 1931. Serial No. 570,601 2 Claims. (01. 209-143) This invention relates to cleaning devices, and more particularly to what Iterm a chip duster.

In the manufacture of wood pulp by chemical processes, it is the common practice to cut the wood up into small pieces or chips approximately three-quarters of an inch square, after which these chips are passed over screens to remove saw-dust and chips larger than the proper size, the screened chips being then suitably treated in digesters in a known manner. In practice, however, an appreciable amount of foreign materials, such as dirt and saw-dust adheres to thechips, and it is desirable that such foreign materials be removed from the chips so that the latter are in a clean condition preliminary to placing themin the digesters'.

One of the main objects of my invention is to provide a device or machine of comparatively simple construction and operation and which is highly efficient in removing foreign materials from the chips. A further object is to provide a machine of the character stated which is continuous in its operation and has a relatively high output. Further objects and advantages of my invention will appear from the detailed description. 1

v In the drawings:-

Figure \1 is a central vertical sectional view! through a cleaning machine constructed in accordance with my invention, taken from front to back thereof, partsbeing broken away and parts being shown in elevation; I

Figure 2is'a back view of the machine;

Figure 3 is a section taken substantially on line 3-3 of Figure 1.

The 'machine includes a main casing 1 comprising a front wall 2 and a back wall 3. The upper portions of these two walls are curved forwardly and downwardly in concentric spaced relation. The lower portion 2a'of front wall 2 is straight and is inclined downwardly and rearwardly of the casing, being disposed tangent to they upper portion of this wall. The lower portion 3a of wall 3 is also straight and inclined downwardly and rearwardly, being disposed tangent to' the upper portion of this wall. The casing, and consequently the passage defined thereby, is of rectangular cross-section, as will be clear from Figure 3.

Referring more particularly to Figure 3, the casing is preferably constructed in two sections provided with laterally projecting flanges 4 by means of which the sections are secured together, conveniently by bolting, or in any other suitable manner. Preferably, suitable gaskets 5 are disposed between the flanges 4 and the edge portions of a suitable screen 6 which is thus secured in position within the casing transversely thereof. This screen extends from the top to the bottom of the casing, the upper edge of the screen being disposed in advance of and adjacent an inlet opening 7 through the top wall of the casing, the lower end of the screen being disposed adjacent and in advance of a discharge opening 8 at the lower end of the casing. An

elbow 9, defining an outlet opening 10, extends from the front wall of the casing at the .lower end thereof. This elbow is connected to a conduit 11 which may lead to a bin or any other suitable point for discharge of air and materials entrained thereby. The screen 6, like thefront and the back walls of the casing, has an upper forwardly and downwardly curved portion and a lower straight portion 6a tangent to the upper portion and inclined downwardly and rearwardly of the casing. It will be noted, however, that the screen 6 is disposed eccentric of the passage and separates such passage into a downwardly diverging air channel 12 and a downwardly converging material channel 13.

l The casing 1 is of substantially uniform crosssection from its upper end to its lower end, as shown in Figure 1. The chips are acted upon to best advantage by the air blast in the flaring upper portion of channel 13, where the major portion of foreign materials is removed from the chips. Any remaining particles of foreign materials are effectively removed from the chips in the lower portionof channel 12, and the chips travel downwardly in this channel by gravity. By having the channels 12 and 13 oppositely related, with the former flaring downwardly and the latter flaring upwardly, as in Figure 1, quick and thorough cleaning of the chips is assured.

The main casing is supported by a frame 14 of suitable type. A fan or blower 15, of known type, is supported upon the frame 14 in a suitable manner and the outletv of this fan is connected, by an upwardly flaring throat member 16, to the upper end of easing 1, this throat member being curved upwardly and forwardly. The blower 15 serves to supply a relatively large volume of air underpressure to the upper end of the main casing 1, the air being projected across the inlet opening 7.

A feed hopper .17 is suitably mounted upon the upper end of a throat member 18 mounted upon the upper end or top of. the casing in register with the inletopening '7. The hopper 17 includes a cylindrical valve casing 19 within which is mounted a rotating valve structure including spaced radial blades 20 provided at their outer ends with flexible packing strips 21 which contact the surrounding wall of valve casing 19 and provide an air-tight seal therewith. Preferably,

there are four'vanes or blades 20 so disposed that the 'valve casing 19 is sealed against escape of the side walls of the casing, this shaft being rotatably mounted at its ends in journal members 23 suitably mounted upon the frame 14. The chips or material to be cleaned are delivered to hopper 17 in any suitable manner, as by means of an endless conveyor 24. I thus provide means for continuously delivering, through the inlet opening 7, chips or material to be cleaned, the chips being discharged downwardly across the stream of air projected into the casing from throat member 16. v

A discharge hopper 25 is suitably. secured to the lower end of the casing in register with the discharge opening 8. This hopper includes a valve casing 26 in which is mounted a valve structure 2'7 similar to the valve structure of hopper 17. The valve structure 2'7 is suitably secured upon a shaft 28 passing through the side walls of valve casing 26, this shaft being rotatably mounted, atits ends, in journal members 29 secured to frame 14. An endless conveyor 30 is disposed beneath the outlet of hopper 25 to receive the cleaned material discharged therefrom, and a baffle plate 31 is preferably secured to the lower end of hopper 25 and extends from the front wall thereof downwardly to within a short distance of the upper run of conveyor 30 fordirecting the discharged material'ontothe conveyor. r a

An electric motor 32 is suitably mounted upon frame 14 and has driving connection with shaft 15a, of fan or blower 15 by means of a belt 33. A countershaft 3,4, suitably mounted on frame 14, is driven from the fan or blower shaft 15a by means of a belt 35. This countershaft has driving connection, by means of belts 36 and 37, with shafts 28 and 22, respectively, of the rotating valve structures. The various shafts referred to are provided with suitable pulleys, as shown, about which the belts are passed, the pulleys being of proper sizes, and the belts being suitably disposed, for driving the fan and the valve structures in proper directions and at proper speeds. Any other suitable or preferred means may be employed for driving the fan or blower and the valve structures.

In the operation of the machine, the chips are delivered by the conveyor 24 to the hopper 17, and thence through opening 7 into the casing. The blower 15 serves to deliver a large volume of air to the casing and the air blast acts to quickly remove from the chips all dirt, sawdust and other foreign materials adhering thereto, such materials passing through the screen 6 and being entrained by the air so as to be discharged therewith through the outlet opening lO. The curvature of the'upper portion of the screen 6 is advantageous as continually changing the direction of travel of the chips in order that the air blast may act to best advantage for removing foreign materials from the chips. As the chips slide downwardly along the straight portion 6a of the screen, any remaining foreign materials adhering thereto are loosened and pass through the screen by the combined action of gravity and the air blast. The cleaned chips are discharged through opening 8 into hopper 25 from which they are delivered by the rotating valve structure 27 onto the upper run of the conveyor 30. The two rotating valve structures, and associated parts, provide means for continuously delivering material to thecasing and removing the cleaned material or chips from the casing, while maintaining the casing sealed against escape of air therefrom except through the outlet opening 10. This renders possible continuous operation of the machine with a corresponding high output thereof, which is highly desirable.

While the apparatus of my invention is particularly well adapted for cleaning chips, I do not in any way limit it to this one use, since it may be used to advantage for many other pur poses.. For example, this apparatus is suitable for cleaning grain' and other analogous materials. As will be understood by those skilled in the art, changes in construction and arrangement of parts of my invention may be resorted to without departing from the field and scope of the same, and I intend'to include all such variations as fall within the scope of the appended claims, in this application in which the preferred form only of my invention is disclosed.

What I claim is:

1. In a cleaning device of the character described, a casing comprising a front wall and a back wall having their upper portions curved forwardly and downwardly in concentric spaced relation, the lower portions of saidwalls being straight and inclined downwardly and rearwardly tangent to said upper portions,'a screen disposed transversely of the casing between the front and back walls thereof, the upper portion of the screen being curved downwardly and forwardly and the lower portion of the screen being straight and inclined downwardly and rearwardly tangent to said upper portion, the easing having material inlet and discharge openings at the top and bottom thereof, respectively, the screen terminating adjacent and in front of said openings, means for projecting airinto the casing toward the front wall and across the inlet opening, the casing having an outlet opening at its lower end and in front of the screen, air-tight means for delivering to'said inlet opening material to be cleaned, and air-tight means for delivering cleaned material from the discharge opening.

2. In a cleaning apparatus of the character described, a casing comprising a front wall and a back wall having their upper portions curved downward and forward, the lower portions of said walls being straight and inclined downward and rearward tangent to said upper portions, a screen within the casing between said walls and defining therewith an upwardly converging air channel at the front of the screen and a downwardly converging material channel at the back of the screen, the upper portion of the screen being curved downward and forward and the lower portion of the screen being straight and inclined downward and rearward tangent to said upper portion, means for projecting air into the casing toward the front wall and across the upper end of the material channel, means for delivering material to be cleaned to the upper end of. the material channel and across the air stream, and -means for discharging cleaned material from the lower end of the material channel, said casing having an outlet opening into the lower end of the air channel.

SIGURD NORMAN. 

